Recording instrument



June 23, 1931.

2 Sheets-Sheet l 'E. H. BRISTOL Filed June 6, 1925 Inven?o?-:

EdgarfLBns 530 Z.

June 23, 1931. E. H. BRIST OL RECORDING INSTRUMENT Filed June 6", 192 5 2 Sheefhs-Sheet 2 QE'dg Fig. 4.

Patented June a 1931 UNITED STATES PATENT o'FFIcE" mien H. BRISTOL, or roxnono, mssnonusnr'rs, nssronon 'ro rm: roxnono coir- PM, or roxnono, mnssncnusn'rrs, a conromrron' or nnssncnusm'rs RECORDING INSTRUMENT Application filed June 6,

p This invention relates to recording instruments such, for example, as recording pressure gages and recording thermometers and more particularly to mechanisms having directly to do with the usual changeable paper. chart or record disc used on such instruments and aims to make the use of the instruments more convenient and the records more accurate.

My invention will best be understood by reference to the following description of the recording instrument shown by way ofexample in the accompanying drawings in which structures illustrative of my invention are embodied. In these drawings:

Fig. 1 is a front elevation of a recording instrument, the usual glazed door being omitted;

Fig. 2 is a side elevation as seen from the right of Fig. 1' with the parts in another position of .adjustment-;

Fig. 3 is a central vertical section with parts broken away, the position of the parts being as in Fig. 2;

, Fig. 4 is an enlarged central section of the chart-holding hub; and

Fig. 5 is a section of the line 55 of Referring to the drawings, 11' have'there shown a recording instrument df well known form embodyin a casing 7, the front of which is closedy a dial plate 9 and which houses a suitable clock movement and a suitable measurin instrumentality such, for instance, as a he ical Bourdon tube or a set of 'diaphragms The measuring i'nstrumentality operates the pen 11 which swings over the dial plate 9v and is adapted to record the conditions measured on the pa er chart 13 which is secured as by means 0 the chart hub 15 to the time shaft of the clock movement to rest against and rotate over the dial plate 9. The instrument would ordinarily be provided with a suitable glazed door, not shown, carried by the hinge knuckles17.

Referring'to Fi 4, he hub 15 by which I the chart is secure to the time shaft 19 ma 4 consist of-an inner part secured to that sha and an outer removable cap. The former preferably comprises. a cylindrical barrel portion 21, the sleeve having 1925. Serial m. 35,352.

the removable cap which preferably includes a sleeve 25 adapted to surround the barrel an annular shoulder 27 opposing shoulder23, the chart beingclamped between these two shoulders with sufiicient pressure to cause the rotation of the same with the time shaft.

To secure the removable cap embod mg the sleeve 25 upon the inner member 0 the hub the latter may be hollowed out toreceive a stem 29 on the cap, a suitable spring catch being provided for engaging the stem within the hollow of the inner element, this catch being preferably arranged to exert a longitudinal'tension. on the removable cap to effect a clamping pressure between the opposed shoulders 23 and 27. In the present embodiment of the" invention the catch is formed by a ball 31 housed in a suitable recess in the inner element so that it PIOJQCtS into the hollow therein, which ball is norinally pressed inwardly by a suitable spring, conveniently in the form of a flat spring in extent somewhat greater than a sem1 circle, which clasps around the inner element of the hub, preferably being housed in an annular groove 35 therein. The end 'of the s ring 33 bears upon the ball 31 gage ina suitable recess 39 in the stem 29 of the removable cap, this recess preferably I being an annular groove asshown to permit engagement of the parts irrespective of the relative angular position thereof and for 7 other purposes which will appear hereafter.

The end of the stem 29 may, as shown in Fig. 4, be provided with a coned inner end cooperating with the convex surface of the rovidea mutual cammmg action ball-.to facilitating the interengagement o! the 1 parts. The rounded surface of the ball entering the groove 2-3 likewise tends to draw the captoward the left in Fig. 4, pressing shoulder 27 against shoulder 23 and may grip the chart with suflicient tightness to insure proper driving of the same from the time shaft. In the preferred embodiment of the invention herein shown the single ball 31 provides a laterally acting :catch tending to press stem 29 laterally (downwardly in Fig.4) into frictional engagement with the wall of the recess in the inner hub element. By this frictional engagement driving of the cap by the inner element carried by the time shaft 19 is assured. To ensure rotation of the chart suitable means are provided whereby the cap grips the same and I have herein shown teeth 41 formed on shoulder 27 of the sleeve 25, the teeth being adapted to pierce the chart when the cap is applied.

The chart as used on these instruments is ruled with suitable lines usually designated with the hours of the day or other time periods. Obviously-if a chart is placed on the instrument at nine oclock in the morning, it should be so positioned that the pen will coincide with the nine oclock line on the chart. In the present instance provision is made permitting angular adjustment of the chart after it has been secured in position on the time shaft. For this purpose the cap or outer member of the chart hub is arranged for rotative movement relatively tothe time shaft. without relaxation of the holdon the chart and means are provided whereby the chart may be rotated with thisouter member orcap inde endently of movement of th time shaft. is has already been noted, the cap may bemanually rotated relative to the inner element of the hub on the time shaft because the ball 31 engages in annular groove 39 in the stem 29 of the cap. Rotative adjustment of the cap to control the angular position of the chart is provided for by the teeth 41 formed on the shoulder 27 which pierce the chart. An annular groove 43 in the shoulder 23 of the inner member receives the teeth 41 and permits rotative movement of the sleeve. Thus, if the sleeve is rotated as by means of the enlarged head 45, the chart will likewise Je rotated by the teeth 41 which grip the same, yet it will be held in the position of adjustment to which it is brought b this rotation and will be rotated by the time shaft at normal speed as soon as the adjusting movement is stopped since the cap which grips the chart by means of the teeth 41 is frictionally clutched to the,shaft with sufficient firmness to effect driving without slippage.

As seen in Fig. 1, the division-lines on the chart indicating periods of time are closer together near the inner circumference of the chart than they are at the outer circumferadvantage may be taken of the larger scale at the margin of the chart and for this purpose the member 47 may be mounted on the edge of the dial plate 9 and have an indicating point 49 projecting inwardly over the edge of the chart to cooperate with the division lines adjacent the outer margin thereof, this point being located in the line of movement of the pen 11. In the embodiment of the invention shown the member 47 is mounted by means of clamping screws in a circumferential slot 51 of the dial plate 9, this providing for the initial adjustment of the member to its roper position in the line of movement of the pen. To facilitate the introduction of the chart beneath the pointer 49', which should lie closely adjacent the same, the member 47 may be provided with a finger 53 curving outwardly from the face of the dial plate, as indicated in Fig. 3, providing in cooperation therewith a guiding passage into which the edge of the chart is readily introduced to be slid to its final position under the pointer 49 whichvlies relatively closely adjacent the face of the chart.

The removable cap of the chart hub is preferably attached to the instrument to prevent its loss. To facilitate its application and removal and also in the present emb0diment of the invention for other purposes the construction best illustrated in Fig. 1 may be adopted. I have there shown the removable cap as swivelled in the end'of a wire bail having its legs 55 pivoted in posts 57 pr0- jecting from the dial plate beyond the margin of the chart. The sides of the bail adj acent the end may be pressed inwardly as indicated in dotted lines at 59 in Fig. 1 to cap. The parts may be assembled by passing the cap between the legs of the bail until the groove lies substantially inthe plane of the latter and then pressing it toward the end of the bail to snap past the shoulders provided by the bending thereof at the points 59. It will be well understood that the pivotal mounting of the cap by means of the ail 55 permits it either to be applied to the time shaft in the position shown in Fig. 1 or snapped free therefrom and swung to one side to the osition shown in.Fig. 2 out of the way of t e chart 13.

The construction of the chart hub herein before described is made by the subject of a divisional application, Serial No. 444,972, filed April 17, 1930.

The chart 13 during operation of the instrument should lie flat and smooth against the dial plate, particularly in the region which lies at any given time beneath the recording pen. For this purpose suitable means may be rovided for holding down the edges of t e chart, that is, for holding them closel confined to the face of the dial plate without, however, ham 1'- ing the rotation of the chart. In the i ustrative embodiment of the invention I have shown a preferred form of holding'means having advantages in itself and also cooperating in a manner which will appear as the description roceeds with other devices embodied in t e instrument illustrated. The holdin means shown may include a relatively hxed device adjacent the upper edge of the instrument, here shown as comprising a wire 63 mountedin a 0st 65 projecting from the edge of the dial plate 9 and bent downwardly closely to overlie the margin of the chart. In the illustrated embodiment of the invention the wire 63 is then bent somewhat upwardly again (Fig.3) and extended inwardly toward the center of the bowed wire 67 chart to provide a bearing sup ort utilized in the'installation of other mec anism presently to be described. The outward bend ing of this extension also provides for guid-' ing the edge of the chart in under the portion of the wire which serves to hold the margin of the chart adjacent the dial plate. The chart ma further be'held adjacent the lower circum erence thereof by means of a pivoted near its ends to the posts 69.project1ng from the dial'plate, the

,2 and 3 to chart ma beneath t e holding means at 63 and en-' main portion of the bowed wire bein adapted to encirclea substantial arc of t e chart adjacent its margin. Because of its pivotal mounting, this owed member may either lie closely adjacent the dial plate in the position shown in Fig. 1 to confine the chart or may be raised to the position of Figs. rovide a clearance between the same and t e dial late through which the be easfiy introduced and slid aged on the barrel 21 of the chart hub %see Fig. 3) or through which the chart may be withdrawn. V

In the embodiment of the invention shown they bowed member 67 is normally s ringpressed toward the raised osition .0 Figs. 2 and 3 and this may be eiiiacted by prov1d ing the bowed member 67 with a cross piece chord-like thereacross, which- 71 extending cross piece may be soldered to the bowed member 67 vad'acent its ends and may have pro ecting en s providing-trunnions pivoti tween its ends the member 71 may be bent to provide a double crank with crank arms 7 3 and'a suitable torsion spring may be interposed between one of the crank arms (that shown at the ri ht in Fig. 1) and the bearing provided by .t e extension inwardly of the member 63. 7

It will be understood that suitable means\ -may the bowed member to the posts 69. Be-

. t umb and fingers for removal.

are provided for holding the member 67 in its lowered position against the force of ber will be raised by the spring freeing the chart for removal and when the cap is applied in position the holding member will be lowered to hold the edge of the chart against the dial plate while the chart is secured to the time shaft by means of the cap. In the form of the invention shown the bail-like handle 55 is utilized to effect this action and it will be clear from Fig. 1 that in the construction shown the lower arm 55 of this bail will bear against the member 67 at a point remote from-the pivotal center thereof and may be utilized to press downwardly the member 67 against the force .of the sprin when the cap isswung inwardly for app ication toits chartholding position at which time thearm 55 ing the face of the chart. Conversely when the cap is removed and swung to the position of Fig. 2, from over the bowed member 67, releasing the same to the action of. the spring which will raise it to the osition of Fig. 2.

I have herein .s own the double throw crank provided on themernber 71 as located so that the wrist of the crank underlies the pen 11, the crank thus serving as a pen. lifter, as clearly appears from Figs. 2 and 3. When the spring 7 5 is permitted to act, the end of the pan will be lifted away from the chart and dial plate and the old chart may be removed and the new one placed in position without any danger of marks being the arm will be removed 4 made thereon by the pen. In the construc-.

the cap, it being lifted from the chart when the cap is removed for the purpose of changing the chart and lowered into cooperation with the new chart when the cap is again applied to clamp the latter.

To facilitate the removal of the chart when released at its mar in suitable means be provided for lifting at least a por tion of the chart from the dial plate 9 so that the fin ers may reach beneath the marin of the c art to grasp the same with the For this purpose I may provide a lever-77 which in the present instance is loosely engaged over and suspended by one of the osts 69 and normally hangs under gravity hatly against the dial late 9. The lever 77 ma have an arm 9 extending inwardly un en the margin of the chart and it willbe underbodiment of the invention stood that if the lever is rocked in the manner shown in Fig. 2 to raise this arm, the edge of the chart underlain by this arm will be raised as shown in that figure and the fingers may readily be introduced under the margin of the chart to grasp the same.

While the movement of the lever might be effected in any desired manner, it may be.

correlated with the other.mechanisms .just described and made consequent in its action on the removal and-application of the cap. Herein the upper end of the lever 81 is bent somewhat outwardly above the post 69 to provide a crank arm which is presented in the path of the extended end 83 of the bowed member 67 so that as the latter swings ,upwardly to the position of Fig. 2 when the cap is removed from the chart hub, the end 83 moving inwardly will rock lever 77, raising arm 79 thereof and causing it to lift the chart. When the cap is replaced and the bowed member 67 again lowered, the lever 77 will return to its position against the face of the dial plate 9 by gravity.

I shall briefly recapitulate the operation of the mechanisms just described in the emillustrated. Suppose that the parts are in the position of Fig. 1 and that it is desired to change the chart. The removable cap is seized and pulled away from the time shaft and swun over to the right in that figure to or toward the position it occupies in Fig. 2. The lower arm 55 is thus moved away from the bail 67, the spring acts on the crank arm 73 and swings the bowed member 67 about the axial line connecting the posts 69, the member 67 moving to the position shown in Fig. 2. As it does this, the wrist of the crank 7 3 lifts the pen 11 away from the dial plate, as shown in Figs. 2 and 3. Also the extended end 83 of the bowed member acts on the end 81 of lever 77 moving the latter to the position illustrated in Fi 2 and raising the edge of the chart. The ngers may then grasp thelower edge of the chart, which preferably, as shown in Fig. 3, still remains engaged over the barrel 21 of the chart hub and by an outward movement it is disengaged from that. barrel and then drawn downwardly and removed from the instrument. A new chart may then be inserted. It is slid upwardly through the wide space between the dial plate 9 and the raised member 67 and beneath the raised pen and its upper edge is slid under the holder 63 adjacent the upper edge of the dial plate. The central opening of the chart is roughly hooked or placed over the barrel 21 of the chart hub in the manner shown in Fig. 3 and it is then sustained in this position and may be .released by the fingers. The cap of the chart hub is next swung downwardly and the parts engaged. When this is done a the bowed member 67 is pressed down again against the action of the spring 75 to hold the lower margin of the chart close to the dial plate. The rocking of the crank permits the pen to be lowered into position to mark on the chart and the lever 77 is released so that the chart may lie flat against the dial plate.

When the removable cap is thus applied, the sleeve 25 will press the chart home over the barrel 21 and against the shoulder 23 toward which it'is pressed by the shoulder 27. When the parts are thus engaged the fingers holding the cap' by means of the head 45 may be turned to rotate the cap independently of any movement of the inner member and of the time shaft and the'teeth 4:1 engaging the chart will move the same relatively to the barrel 21 and the chart may be brought into proper position of angular adjustment after it has been applied to and secured to the time shaft.- The pointer 49 facilitates getting this adjustment accurately and quickly.

It will be understood that in referring to the chart as resting against the dial plate and as being held down at the margins I do not mean that it is clamped against the plate but merely that it is supported closely adjacent thereto and is maintained fiat and smooth but free for easy rotation over the face of the dial plate.

I have described in considerable detail the particular embodiment of my invention shown by way of exam le in the accompanying drawings. It is o vious that the structure shown is highly organized. In particular provision 'is made for releasing the chart, for raising the pen and for lifting the margin of the chart and all these operations are coordinated one with another and are made conse uential upon the application and removal of the cap of the chart hub. Obviously various of these mechanisms might be utilized in other combinations or certain of the functions dispensed with, some or all of them might be independently operated or operated by other means, whether in one or both phases, and devices of different structure might be utilized to effect one or more. of the functions described. The construction shown and described in detail is therefore to be understood as a preferred and highly refined-embodiment of more generic principles and what I claim as new and desire to secure by Letters Patent I shall express in the following claims.

Claims:

1. A recording instrument comprising a dial plate, a time shaft for supporting a chart to rest against and rotate over said plate and means for holding the margins of the chart including a bowed member secured at its ends to the plate and having a main portion encircling a marginal portion of the chart and beneath which the chart may he slid for attachment to said shaft.

2. A recording instrument comprising a dial plate, a time shaft for supporting a chart to rest against and rotate over said plate and means for holding the margins of the chart including a bowed member pivoted at 7 its ends to the plate and having a main portion encircling a marginal portion of the chart and swingable alternatively to hold the chart close to the plate or to provide a clearance facilitating the application of the chart.

' 3. A recording instrument comprising a dial plate, a time shaft for supporting a chart to rest against and rotate over said plate and means for holding the margins of the chart including a bowed member pivoted at its ends to the plate and having a mam portion encircling a marginal portion of the chart, a spring normally acting to swing said portion away from the chart, a removable cap for securing the chart -to the time shaft and a carrier for the cap arranged to move the member against the spring when the cap is applied. 1

4. .In a recording instrument in combination with a dial plate, means for'holding a chart thereagainst for rotation thereover comprising an element on the dial plate extending over the edge of the chart at one side thereof, a bowed member pivoted near its ends on the plate and having a main portion encircling the margin of the chart on the opposite side and pivotally movable alternatively to a position holding said margin to the plate and to a position providing a clearance through which the chart may be inserted or withdrawn from beneath said element.

5. In a recording instrument in combination with a dial plate, means for holding a chart thereagainst for rotation thereover comprising an element on the dial plate extending over the edge of the chart at one side thereof and extended to provide a bear- ,ing for a spring, a bowed member pivoted near its ends on the plate and having a. main portion encircling the margin of the chart on the opposite side, a crank carried by said member, a spring interposed between said bearing and crank and means for holding said member in position against the force of said spring.

6. A recording instrument comprising a dial plate, a time shaft projecting therethrough, means for attaching a chart to the time shaft to rest against and rotate over the dial plate, said means comprising a removable cap, hold-down means on the dial plate adapted to extend over the margin of the chart and movable toward and from the same, and means for holdingsaid holddown means inoperative position actuated by the movement of applying said cap.

7. A recording instrument comprising a dial plate, a time shaft projecting therethrough, means for attaching'a chart to the time shaft to rest against and rotate over the dial plate, said means comprising a removable cap, hold-down means on the dial plate adapted to extend over the margin of the chart andmovable toward and from the same, and means for. automatically lifting said hold-down means away from the chart rendered effective-when said cap is removed.

8. A recording instrument comprising a dial plate, atime shaft, means for attaching a chart to the shaft to rest against and rotate over the dial plate comprising 'a barrel on the shaft over which the chartmay freely be placed, means for clamping the positioned chart to rotate with the shaft and means on the dial late opposing the margins of the chart to old them close to said plate, said means being movable at least in part to provide a clearance between the same and the dial plate through which the chart may be slid and placed over'said barrel.

9. A recording instrument comprising a dial plate, a time shaft, means for attaching a chart to the, shaft to rest against and ro-' tate over the dial plate comprising a barrel on the shaft over which the chart may freely be placed and a removable cap for clampingthe positioned chart to rotate with the shaft and means on the dial plate opposing the margins of the chart to hold them close to the plate, said means being operatively associated with said cap to move' at least in part when said cap is removed to provide a clearance between the same and the dial plate through which the chart may be slid and placed over said barrel.

10. A recording instrument comprising a time shaft and means for securing a chart thereto having a removable cap, means for holding down the edge of the chart having a permanent mounting on said instrument permitting movement of said means itself and means for moving said holding means to and from operative position respectively when the cap is applied and removed.

11. A recording instrument comprising a time shaft and means for securing a chart thereto having a removable cap, an arm piv j dial plate, a time shaft, means for attaching a chart to the shaft to rest against and rotate over the dial plate comprising a barrel 7 on the shaftover which the chart may freely be placed and a removable cap for clamping the ppi sitioned chart to rotate with the shaft dial to ho whenthe cap is applied. 7 14. A recording'instrument comprising a and dial plate, a time shaft, means for attaching a chart to the shaft to rest upon and rotate over the dial plate and a lever underlying a marginal portion of the chart and movable to lift the same for grasp by the fingers to facilitate removal of the chart.

15. A recording instrument comprising a dial plate, a time shaft, means for attaching a chart to the shaft to rest upon and rotate over the dial plate comprising a barrel over which the chart may be freely placed and means for clamping the chart to rotate with the shaft and a lever underlying a marginal portion of the chart movable to lift the edge of the same from the dial plate for gras ing with the fingers to facilitate removal 0 the chart from said barrel.

16. A recording instrument comprising a dial plate, a time shaft, means for attaching a chart to the shaft to rest upon and rotate over the dial plate, said means comprising a support for t e chart and a removable cap and a piece underlying a marginal portion- -of the chart to raise the same for grasp by the fingers, said piece operatively connected to said cap for movement to raise the chart when the cap'is removed.

17. A recording instrument comprising a dial plate, a time shaft, means for attaching a chart to the shaft to rest upon and rotate over the dial plate, said means comprising a support for the chart and a removable cap and a piece underlying a marginal portion of the chart to raise the same for grasp by the fingers,said piece operatively connected to said cap for movement to raise the chart when the cap is removed, said connections providing for return of the piece to inoperative position when the cap is replaced.

18. A recording instrument comprising a dial plate, a time shaft, means for-attaching a chart to the shaft to rest upon and rotate over the dial plate, said means comprising a support for'the' chart and ai removable cap, a piece underlying the chart to move at least a part of the same away from said dial plate, said piece being operatively connected to said cap for movement to move the chart when the cap is removed.

19. A recording instrument comprising a dial plate, a time shaft having a barrel over which a chart may be placed to rest against and revolve over said dial plate, means opposing the margin of the chart to hold it close to the dial plate, said means being movable toward and from the plate and a device having an arm underlying a marginal 'portion of the chart for lifting the same a cap for securing the chart to the barrel to rotate with the chart having a mounting constructed to move said holding means toward the chart against the spring pressure when the cap is applied and a device having an arm underl ing a marginal portion of the chart for lifting the same from the plate for grasp by the fingers to facilitate removal of the chart from the barrel and a portion in the path of said holding means to be operated thereby.

21. A recording instrument comprising a dial plate, a'time shaft for supporting a chart to rest against and rotate over said plate, means for holding the margins of the chart including a bowed member pivoted near its ends to the dial plate and having a main portion encircling a marginal portion of the chart, a lever having an arm underlying the chart and an arm in the path of an end of said member whereby the first arm is raised to lift the chart when the member is swung to release the chart and means for controlling movement of said parts.

22. A recording instrument comprising a dial plate, a time shaft for supporting a chart to rest against androtate over said plate, means for holding the margins of the chart including a bowed member pivoted near its ends to'the dial plate and having a main portion encircling a marginal portionv of the chart, a lever having an arm underlying the chart and an arm in the path of an end of said member whereby the first arm is raised to lift the chart when the memberis swung to release the chart, a removable cap for'securing the chart to the shaft and a mounting for said cap for controlling'said member and lever through the application and removal of said cap.

23. A recording instrument comprising a dial plate, a time shaft, means for attaching a chart to said shaft to rest upon and over the dial plate, means movable toward and from the margin of the chart for holding it close to the dial plate, a piece underlying the chart and operatively correlated with said means to be lifted when said means are moved away from thechart whereby to raise the chart.

25. A recording instrument comprising a dial plate, a time shaft, means for attaching a chart to said shaft to rest upon and rotate over the dial plate, comprising a barrel on the shaft over which the chart may be freely placed, means movable toward and from the margin of the chart for holding it close to.

the dial plate, a piece underl ing the marginal portion of the chart which is released for lifting when said means are moved away from the chart thereby to raise a margin of the chart to be grasped by the fingers to facilitate the removal of the chart from the barrel.

26. A recording instrument comprising a dial plate, a time shaft, means for attaching a chart to the shaft to rest upon and rotate over the dial plate, said means c0mprising a support for the chart and a removable cap, means opposing a marginal portion of the chart for holding it close to the dial plate movable toward and from the same, means underlying a portion of the chart movable to lift the same, both said means being operatively connected with said cap to provide for release of the chart and raising of the same on removal of said cap.

27. A recording instrument comprising a dial plate, a time shaft, means for attaching a chart to the shaft-to rest upon and rotateover the dial plate, said means comprising a support for the chart and a removable cap, means opposing a marginal portion of the chart for holding it close to the dial plate movable toward and from the same, means underlying a portion of the chart movable to liftthe same, both said means being operatively connected with said cap to prov de for return of said underlying means to nonchart-raising position ,andof said holding means to position against the chart when the cap is applied. 1 v v 0 v 28. A recording instrument comprising a a time shaft projecting therethrough, means for attaching a chart to the time shaft to rest upon and rotate. over the dial plate, said means comprising a removable cap, a pen cooperating with the chart, a device for lifting the pen, hold-down means on the dial plate adapted to extend over the margin of the chart and movable toward and from the same, means carrying the cap operatively associated with said device and hold-down means to provide for lifting the en and freeing the margins of the chart w en said cap is removed and for.

lowering the penand holding the margins of the chart when the cap is applied.

v29. A recording instrument comprising a dial plate, a time shaft projecting therethrough, means for attaching a chart to the time shaft to rest upon and rotate over the dial plate, said means comprising a removable'cap, a pen cooperating with the chart,

a device for lifting thev pen, hold-down means von the dial plate adapted to extend over the margin of the chart and movable toward and from the same, means carrying the cap effective when the cap is in position to hold the chart to hold said device to permit the pen to cooperate with the chart and [to hold said hold-down means in operative position relatively to the chart marn. 30. A recording instrument comprising a dial plate, a time shaft projecting therethrough, means for attaching a chart to the .time shaft to rest upon and rotate over the dial plate, said means comprising a removable cap, a pen cooperating with the chart,

a device for lifting the pen, hold-down means on the dial plate adapted to extend over the margin of the chart and movable toward and from the same, means carrying the cap effective when the cap is removed .to release said hold-down meansand to raise the pen.

31. A recording instrument comprising a dial plate, a time shaft, means for attaching a chart to said shaft to rest upon and ro' tate over said chart comprising a barrel onthe shaft over which the chart is placed, a pen cooperating with the chart, means for lifting the pen from the chart, a piece underlying a marginal portion of said chart movable to lift said portion for grasp by the fingers to facilitate removal of the chart 7 from said barrel, said pen lifting means and said piece being connected to provide for their conjoint action in raising movement.

32. A recording instrument comprising a dial plate, a time shaft, means for attaching a chart to said shaft to rest upon and rotate over said chart comprising a barrel on the shaft over which the chart is placed, a pen cooperatin with the chart, means for lifting the pen rom the chart, a piecenunderlyinga marginal portion of said chart movable to lift said portion for grasp by the fingers to facilitate removal of the chart from said barrel, said pen lifting means and operating said means on removal and application of the cap.

34. A recording instrument comprising a dial plate, a time shaft projecting therethrough, means for attaching a chart to the time shaft to rest upon and rotate over the dial plate, said means comprising a removchart is freed and the able cap, a pen cooperating with the chart, a device for lifting the pen, hold-down means on the dial plate adapted to extend over the margin of the chart and movable toward and from the same, said means connected to operate in unison, whereby the margin of the pen is raised together and the chart held and the pen lowered together. v

35. In a recording instrument in combination with a dial plate, a pen movable thereover, means for holding a chart against said plate comprising an element on the plate extending over the edge of the chart at one side thereof, a bowed member pivoted near its ends to the plate and having a main portion encircling the margin of the chart on the opposite side and pivotally movable alternatively to a position holding said margin to the plate and to a position providing a clearance throu h which the chart may be inserted or withdrawn from beneath said element and a bar extending chord-like across said member and beneath the penand providing a crank to raise the pen when the bowed member is raised from the chart.

' 36. In a recording instrument in combination with a dial plate, a pen movable thereover, means for holding a chart" against said plate comprising an element on he plate extending over the edge of the chart at one side thereof and extended to provide a bearv .thereto having a removable egg, 8. un

ing for a spring, a bowed'member pivoted near its ends to the plate and havin a main portion encircling the margin of the chart on theopposit'e side, a bar extending chord like across said member and bent to provide a double throw crank, the wrist of the crank underlying the pen, a spring between said a means for bearing and a crank-arm and ber pivoted to t 'thecap is removed or applied.

38. A recording instrument comprising a time shaft and means for securing a chart thereto having a removable cap, a bail pivoted to the instrument and partly encircling the margin of the chart, a pivoted arm car- .rying the ca and adapted to press the bail toward the ciiart when the cap is applied.

.39. A recording instrument comprising a time shaft and means for securing a' chart thereto, a bail pivoted to the instrument and partly encirclin the margin of the chart and manipulatale means .for holding the bail in ositions respectively close to and. distant om said chart.

40. A recording instrument comprisin a dial plate, a time shaft,'meai1 s'for attachlng a chart to the shaft to rotate over the dial plate comprisin a removable/cap, a'meme dial plate and having a portion swinging into proximity to a margin of the chart to hold it close to the dial and connected with said ca to move toward and from the chart when t e cap is'applied and removed respectively.

In testimony whereof, I have signed my name to this specification.

EDGAR H. BRISTOL.

holding said member against the force of.

said sprmg.

37. A recording instrument comprising a time shaft and means for securing a chart operating with the chart, a cra I the pen, a spring tending to rotate the cran in one direction and an arm to rotate thecrank'against the spring, said arm carrying i 

